Magnetic tape data storage cartridges provide long term storage of information on the magnetic tape. Magnetic tape data storage drives read and write data to the magnetic tape in the data storage cartridges. Data is written to the magnetic tape in the data storage cartridge by the magnetic tape data storage drive. Typically, a mechanism is used to load the tape onto a tape path in the magnetic tape data storage drive from a data cartridge. The mechanism may include a moving leader block that attaches to the end of the tape in the cartridge, and then moves away from the cartridge (or file reel) towards a machine reel such that the tape trails the block and is positioned between a guiding surface and a head(s).
Lateral motion of magnetic tape during read/write operations imposes constraints on the spacing of data tracks, and thereby the areal storage density that can be achieved on the tape. One approach to reducing lateral tape motion includes using high wrap angles of the tape around the guiding surfaces. Another approach includes using guide mechanisms, tools, structures, or devices for guiding the tape on its non-magnetic backcoat. A further approach includes positioning guides close to the head on either side or both sides of the head. In some embodiments, for maximum effectiveness, the above approaches are combined.
However, drawbacks of known approaches to reduce lateral motion of the tape result in at least the following problems. For example, the narrow spacing between the guides and the head does not allow a typical leader block mechanism to thread the tape path. In this case, where sufficient space is unavailable for a leader block mechanism, a leader tape mechanism is used whereby a length of leader tape always remains in the path, and the leader tape attaches to the end of the data tape and threads it in the path. However, redesigning a tape drive and replacing the leader block mechanism with a leader tape mechanism involves significant design and manufacturing changes and costs, along with constraints due to the limited available space. Such design and manufacturing changes require additional undesirable costs related to redesigning, manufacturing, and labor.
Additionally, another problem with current guide mechanisms is when using a stationary guide. When using a stationary guide, high frictional forces between the tape and the guide at the time of start up of the tape can cause the tape to stick to the surface, thereby potentially causing tape damage at the instant the tape starts moving from a stopped position. This problem can be compounded by the high wrap angles of the tape around the guides resulting in additional friction, and potential damage to the tape.
It would therefore be desirable to provide a system and method for threading a tape through a magnetic tape data storage drive from a data cartridge when the drive includes a mechanism to control lateral motion of the tape. There is a further need for the system and method to be cost efficient, including manufacturing costs and labor costs. Additionally, there is a need for a system and method to thread the tape through the storage drive without causing undesirable frictional forces on the tape during threading and during operation with frequent stopping and starting of the tape.